Save As corrupts file, refuses to upload

Well, that's an improvement.

If it happens again, Go to Site ⇒ Advanced ⇒ Recreate Site Cache. 

I've never seen anything like it either.  I've used dreamweaver for over 20 years, about 15 for php.  I'm not sure what version I was on earlier, but two days ago I got the latest version from Creative Cloud and it was doing the same thing.

Interestingly, I copy/pasted the file again in windows explorer, and uploaded it to the server using cPanel.  Later, Dreamweaver picked up on the new version and had a pop up, "This file has been edited outside of dreamweaver.  Do you want to update the file?" or something along those lines.  I said yes.  That seemed to finally strip this crazy formatting/caching that dreamweaver had around the file and it works now... at least for now.

I work with PHP files on a regular basis. I've never encountered this behavior. 

Which version of Dreamweaver?

Which operating system and build #?

Have you tried Restoring Preferences? 

https://helpx.adobe.com/dreamweaver/kb/restore-preferences-dreamweaver.html

I tried to get around these issues by copy/pasting the file in windows explorer instead of doing it indreamweaver.  But when I open this version in dreamweaver, it's also wonky (see screenshot).  To be clear, if I copy/paste the file, and name it a NEW name that dreamweaver hasn't encountered before, it opens just fine.  It's ONLY if I rename the file as the old/original functions file name, that it freaks out like this.  You can see below, it added spaces on every second line.  This function overall can't be minimized, but parts of it look auto-minimized.  But when I click on the arrow, i can't open this block.  Again, teh original file, and any copies with new file names work, compile, upload fine.  It's only weird like this when I name it the same old existing file name.

Please see the attachment I added to this post.  It shows a screenshot.  The code is fine.  I have the working file which uploads, compiles and works totally fine.  It's only when I "save as" the older, original file, that version becomes unworkable.  I understand that wonky isn't helpful but I don't even know how to describe it.  The code is identical, or should be.  But it's Dreamweaver's rendering that's all.. wonky.  In the old version, I can collapse and expand functions.  In the new one I can't.. Some are collapsed.  Some are expanded.  Some can't be collapsed.  Some are half collapsed, half expanded.  There are these grey blocks that I think are meant to show minimized code but instead they're showing up randomly through expanded code (see attachment).  It seems like Dreamweaver has some old cached formatting for the old version of this file that it's superimposing.  I tried deleting the file completely and "save as'ing" anew but it doesn't help.

Have you checked that your document is free of coding errors?

Window => Results => Validation

Wonky is an inexact, technically unhelpful term.

It tells us nothing about what's in your code or why saving the file would make it break.

Can you provide examples of Before & After code? 

And tell us it's relative file path when it was working vs when it stopped working. 

This is a very serious problem... I just released a new layout on a website that gets 20,000 visitors per day, and I am completely unable to edit my main functions file that controls the website.